Answer:
Never
Step-by-step explanation: If two points are on the same plane but a line containing those two points is not on the same plane, the statement will never be true. Picture a cube and on one face of the cube lies two points, if there is a line containing those points, the line also has to be on the same side or face. It will always run parallel to the same side but will also always be touching that side.
Step-by-step explanation:
-8 and 8 would work :)
<u>Given:</u>
Ratio of white and blue paint is 2:3
Total quantity of paint is 20 litres
<u>To find:</u>
Quantity of blue paint to be mixed so that the ratio of white paint to blue paint becomes 1:7
<u>Solution:</u>
The ratio 2:3 totals 20 that is 
So, the quantity of white paint in the mixture is 
and the quantity of blue paint in the mixture is 
Now, to get the final ratio as 1:7, Mary should have 
of blue paint. So, she need to add 
.
Therefore, Mary has to add 44 litres of blue paint to the mixture to make the ratio as 1:7.
x - 2y + z = 5 | *2
⇒ 2x - 4y+ 2z=10
3x + 3y - 2z = - 6 } I sum up these relations
--------------------------------
2x+3x - 4y+3y+2z-2z=10-6
5x - y = 4 (1)
3x + 3y - 2z = - 6 | *3 ⇒ 9x + 9y - 6z = - 18
2x - y + 3z = 11 | *2 ⇒ 4x - 2y + 6z= 22 I sum up these
----------------------------------
⇒ 9x+4x+9y-2y-6z+6z= 4
13x+ 7y= 4 (2)
I write (1) and (2)
5x - y = 4 | *7
35x - 7y= 28
13x+7y=4
48x = 32
x= 32/48=4/6 ( 32:8=4, 48:8=6)
x= 2/3
5x-y=4,
5*2/3-y=4
y=10/3 -4=10/3-12/3=-2/3
⇒ y= - 2/3
x - 2y + z = 5
2/3 - 2*(-2/3)+z=5
2/3+4/3+z=5
6/3+z=5
2+z=5
z=3
x+y+z=2/3-2/3+3=3
x+y+z=3
